Although China tirelessly asserts it, there is not one China. There are, rather, four Chinas - the Communist mainland, Portuguese Macao, British Hong Kong, and Kuomintang-ruled Taiwan.
And, while Peking decides what to do with Macao and Hong Kong, it must keep a wary eye on Taiwan's reactions.
After the left-wing revolution in Portugal in 1974, there were those in Lisbon who imagined Peking would be delighted to take back Macao. The Chinese rejected it, making clear they alone would decide the right time for reversion.
It has been widely assumed that Peking realizes a Chinese takeover of Macao would have administered a serious, possibly fatal, blow to the business confidence of thriving Hong Kong, which, like Macao, was originally Chinese territory now ruled by foreigners.
Similarly, the Chinese Communists are presumably aware that to take over Hong Kong would reduce to the vanishing point the already slight chance that a future Taiwan government would negotiate reunification with the mainland.
A Chinese miscalculation on future arrangements for Hong Kong could send entrepreneurial talent, money, and refugees from Hong Kong to Taiwan - much as all three have come to Hong Kong from China since 1949. Apart from strengthening the island's economic prospects, this would put the seal on Taiwan separateness.
The effect on Taiwan could be more positive if Peking agrees to an arrangement whereby Chinese nationalism is somehow satisfied, but Hong Kong's separateness and economic growth are left untouched.
All this assumes China sees the linkages. Recent interplay between China and the US over Taiwan suggests otherwise.